Connor Lind was convicted on two counts of sexual intercourse with and one count of sexually touching a person under the age of 16, following a Sydney District Court trial in September.
The now 23-year-old was cleared on two other similar charges and continues to deny any wrongdoing.
On Friday, Lind was sentenced to spend at least 11 months behind bars, but instead left the court on bail following an immediate intervention by his lawyer.
Defence barrister Lisa-Claire Hutchinson told the court Lind would be appealing both the convictions and sentence, and successfully applied for him to be bailed in the meantime.
Judge John Pickering granted bail on the likelihood an appeal hearing would not occur until Lind had already served the bulk of his sentence.
However, he noted should Lind lose the appeal, he will most likely have to serve his sentence from that time, extending his potential release date.
"He makes this application with his eyes wide open to that outcome," Ms Hutchinson said.
Lind was 19 at the time he pursued a sexual relationship with the girl, sending her messages and a Christmas card expressing what the court accepted were genuine feelings for her.
Judge Pickering accepted Lind's offending wasn't "predatory", but said he had no choice but to impose a period of full-time jail.
"There has to be a reflection of the seriousness of this offending," Judge Pickering told the court.
"He knew that he was well and truly over-age - he knew her age - and he decided that he would behave in this fashion."
In a victim impact statement, the girl said her experience with Lind had made her "grow up much quicker" and become cynical about men potentially using her purely for sexual purposes, the court was told.
Judge Pickering said the girl's statement is a good example of why society expects grown-up men like Lind to leave 14-year-old girls alone.
"We actually don't want as a society, someone in year nine engaging in a sexual relationship with someone who is well and truly out of high school," he told the court.
Judge Pickering said Lind's offending may end completely a once-promising sporting career, particularly in rugby sevens.
During the trial, it was submitted by Lind's lawyers the stereotype that young men could not control themselves sexually was untrue.
"As it turns out ... he could not control himself," Judge Pickering said.
"He chose to pursue this. He pursued it with vigour.Â
"He wrote love letters, he provided a ring, created situations where they could be together."
Conditions of Lind's bail include that he report to police every Monday and surrender his passport.
1800 RESPECT (1800 737 732)
National Sexual Abuse and Redress Support Service 1800 211 028
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